The present invention is concerned with massage devices for therapeutic uses. Massage devices for therapeutic uses, such as disclosed in U.S. Pat. No. 4,098,266 to Muchisky, have been known in the prior art. Such devices create massaging action through the rotation of an eccentric weight within an applicator head. Prior art massage devices have had drive cables with drive keys at their ends coupled to a motor shaft, and to the massage applicator shaft. However, with such couplings linear movement of the cable relative the couplings is inhibited.
Swivel couplings for drive cables are known in the prior art, such as in Muchisky U.S. Pat. No. 4,098,266 which uses a set screw to couple a pair of sleeves. However, it is desirable to have swivel couplings composed of parts that evenly distribute force and can be conveniently assembled and easily handled, yet not easily lost or misplaced.
In prior art massage applicators, separate components are used to accommodate the transmission of power into the applicator. The number of such components increases the time spent in assembly of the applicators, and increases the potential for malfunction of the applicator.
Prior art applicators have used bearings for the transmission shaft, but there has been a need for a bearing located at the maximum stress point close to the rotating eccentric that is stronger than the other bearing material for the shaft.
In the prior art applicator belts have been used to hold a massage applicator to the body. However, belts such as in Muchisky U.S. Pat. No. 4,098,266 have pockets which limit the positioning of the applicator onto the body, and the presence of such pockets also requires more material and labor to be involved in their production than is desired.
In the prior art there is also a need for a massage apparatus having a handle for the power unit and the applicator so that both can be gripped by the hand while the applicator is mounted and secured to the power unit.
It is furthermore desirable to have massage applicators with a minimum of watertight seals to allow use of the applicator under water.
The present invention improves over the prior art. The invention comprises a power unit which has a motor driven shaft to transmit rotary power through a cable to a massage applicator. The massage applicator has a head containing an eccentric driven by a drive shaft which is connected to the cable within the applicator.
The invention comprises means at both the power unit and at the applicator to allow the cable to be slidingly connected for drive transmission so that the cable can slide to accommodate forces exerted upon the cable by coiling and straightening. Such sliding connection recuces friction during cable rotation, reduces stretching of the cable, reduces heat generated by rotation of the cable, reduces the change in the number of RPMs for cable rotation, and reduces stress on the cable.
At the power unit the motor shaft has an outer bore, and a connector member which fits about the motor shaft. The connector has an extension projecting from the shaft which extension has a bore therethrough having a square surface. The flexible drive cable has both of its ends squared to provide drive keys, with the first key extending within the square of the extension to be drivingly and slidingly engaged therewith. This allows rotation of the motor shaft to rotate the cable, but also allows the cable key to slide relative to the connector within the bore of the motor shaft.
At the other end of the cable at the applicator, another sliding-drive connection is provided between the second cable key and the drive shaft of the applicator. The applicator drive shaft has an end bore having a square inner surface which extends into a second bore of larger size. The square bore of the drive shaft slidingly receives the second squared key to be drivingly engaged therewith. However the shaft bores allow the second cable key to slide relative to the applicator to allow cable movement in the response to forces exerted upon the cable.
Thus at both ends of the cable, accommodation for cable movement is provided.
The invention furthermore comprises unique swivel couplings at both ends of the cable. The cable is surrounded by a flexible plastic sheath. At the power unit, a bell sleeve is secured to the power unit and surrounds the motor shaft and the connector. The first end of the sheath firmly fits within one end of a first ferrule sleeve. The ferrule has an outwardly extending cylindrical flange at its end opposite that which receives the sheath. The ferrule flange is fitted against the end of the bell sleeve and secured thereto by a cylindrical nut which fits around the ferrule to hold the ferrule flange against the bell sleeve so that the ferrule may swivel relative thereto.
At the second end of the cable and sheath, a second swivel coupling is provided. A second ferrule firmly receives and holds the second end of the sheath. The second ferrule has a shape similar to the first ferrule, and has an outer end cylindrical flange which fits within a cylindrical bore of the applicator. The second ferrule flange is held in place by a nut which fits around the ferrule and screws into the handle of the applicator to allow the second ferrule to swivel relative to the applicator.
In the case of both swivel arrangements, the nuts are of sufficient size to be handled easily, and both nuts distribute the retaining force evenly against the ferrules, rather than apply force at a single point.
The present invention further comprises a belt arrangement in which a strip of latching textile hook material, such as sold under the trademark Velcro, is secured firmly to the rear side of the applicator head, with the belt being provided with interior and exterior receptive Velcro textile pile surfaces so that the applicator can be latched to the belt. The applicator can be latched in such a fashion that it is not restricted by the confining dimensions of a pocket or other arrangement, and this allows for greater freedom of positioning of the applicator as well as eliminating material required.
The applicator is provided with a watertight seal at its lower end, and its head is divided into two parts which are fitted flush against each other and secured with a watertight seal so as to prevent seepage of water.
The applicator is comprised of a housing made of molded plastic, which is divided at the head end of the applicator into two parts, a top head section, and a lower part. The lower part is molded so as to provide a passageway for the transmission of the drive of the cable to rotate the eccentric shaft and the eccentric. The applicator structure is such that separate parts to provide the transmission are reduced and ease in assembly and repair is facilitated.
The shaft within the applicator is subjected to maximum stress at the end adjacent the eccentric. The present invention comprises a bearing at two locations of the shaft, with the bearing nearest the eccentric being of greater strength than the farther bearing.
The invention further comprises a combined handle and mounting member on top of the power unit. The handle mount has a curved U-shaped upper recess to receive the elongated end of the applicator handle. A projection at the end of the applicator handle fits into a slot in the interior surface of the handle mount so as to prevent movement of the applicator along the handle mount. Two knobs extending from the interior side of the handle mount interior surface are resilient enough to allow the applicator handle to be pushed down beneath the, but yet hold the applicator against the weaker forces which can be applied to the applicator due to jostling or improper handling, but allows the applicator to be removed by a firm upward pull of the hand. The fit of the applicator handle within the handle of the power unit is such that a single hand can be gripped around both to carry the power unit and the applicator.